Calibration gone wrong?!

[Dan13]

Hi, Long story short....

36 days and counting before i managed to get back out under the night sky and start imaging again! Needless to say i felt like i had never imaged before it felt soooo long!

Anyways, i shot 6 hours on the Heart nebula and to say im disappointed with the final stack is an understatement, it looked A MESS! possibly the worse acquisition ive carried out. Now ive seen this issue before but properly calibrated frames has always resolved this but this time however no calibration frames at all worked better then any! Please see below final stack and DBE carried out with flats and flat dark's and same again without any calibration frames at all. it seems my calibration frames are not subtracting but instead adding to my image??

Any ideas would be greatly appreciated , ive also added my final edit of this target from the data i had and to get the best out of it i went starless...

 

Cam used is a Asi 294mc pro with the optolong Lenhance filter shot at 240sec x 89 over 2 nights. calibration frames (flats/flat darks taken on both nights) seeing wasnt the greatest...

 

Dan

[david_taurus83]

No darks? The flat darks only calibrate the flat frames. You need 240s darks at the same gain and offset to calibrate the lights. That should sort out the amp glow.

[Dan13]

On 16/09/2020 at 18:30, david_taurus83 said:

No darks? The flat darks only calibrate the flat frames. You need 240s darks at the same gain and offset to calibrate the lights. That should sort out the amp glow.

Apologies i didnt get notified about your reply. its not the amp glow that concerns me as i can get rid of that, its the red outer rings everywhere thats my issue

[SyedT]

What ADU/histogram value did you aim for when taking the flats? It looks like the flats are over-correcting. 

[Dan13]

16 minutes ago, SyedT said:

What ADU/histogram value did you aim for when taking the flats? It looks like the flats are over-correcting. 

the flats were generated via N.I.N.A 's flats wizard I've never had an issue with the flats wizard before so may check to see the settings are ok after the recent update i guess, but you could be right here...

[SyedT]

Just now, Dan13 said:

the flats were generated via N.I.N.A 's flats wizard I've never had an issue with the flats wizard before so may check to see the settings are ok after the recent update i guess, but you could be right here...

When I was using a ZWO ASI 1600MM, I found that it was very sensitive to even slight changes in settings/stray light. You're doing the right thing by using flat darks, as the low exposure time for bias settings can cause the camera to behave unpredictably from my experiences. 

I would suggest you check your settings, and even if they're fine, to re-take the flats with the rest of the scope/camera covered up to ensure there's no stray light entering the imaging train.

[Dan13]

Just now, SyedT said:

When I was using a ZWO ASI 1600MM, I found that it was very sensitive to even slight changes in settings/stray light. You're doing the right thing by using flat darks, as the low exposure time for bias settings can cause the camera to behave unpredictably from my experiences. 

I would suggest you check your settings, and even if they're fine, to re-take the flats with the rest of the scope/camera covered up to ensure there's no stray light entering the imaging train.

Will do that for sure. the weird thing is it happens when using the L-Enhance and not the Lpro so i dont know if its related to the filter/cam combo or not? tbh ive read a few issues with this combo but its very widely used so cant see it being at fault. Ill dive into the flats wizard settings again and see if i haven't updated something. ive got a feeling i slightly changed my gain and offset since the last flats run ...